Off Grid Living

 

Offgrid solar is a term that's often misunderstood. In it's purest form an off grid solar system is any system regardless of size or runtime that provides electric power independent from the utility company's electric grid.

Depending on your needs an offgrid solar system can be as simple as a single small wattage solar panel, a pulse width modulated charge controller that regulates power from that solar panel, a battery, and a DC to AC inverter or it can be as complex as a much larger, roof or ground monted solar array involving several solar panels connected to a fused combiner box, multiple MPPT (multi point power tracking) charge controllers, a grid tie capable, DC to AC inverter/charger with transfer switch and multiple batteries wired in a series/parallel configuration to boost energy storage capacity to increase system runtime.

Offgridsolar.com specializes in all forms of off grid applications, whether that be a system for a small remote cabin or a system that can maintain the operations of a large manufacturing facility. An emerging market today is the installation of a grid tied battery backup system. In this time of application, a DC to AC inverter in used that has the ability to synchronize it (sinewave) waveform to the electric grids frequency and voltage.

Under normal operation, a grid tie battery backed system takes DC energy from the solar panels and feeds that energy to a bank of batteries. The batteries are kept from being overcharged by a device known as a charge controller. A charge controller limits the amount of current that is fed to the batteries so that the batteries are maintained in a constant state of charge.

Once the batteries are fully charged, they are kept in that state by applying a trickle charge which bleeds off a very small amount of current from the solar panels. The bulk of this DC current is then fed to the DC to AC grid tied inverter and is converted into 240 Volt 60 Hertz AC (alternating current) which can be used by your home's appliances. Excess energy that is not used by your home's appliance is fed through the utility company's electric meter which causes it to slow down or spin backwards.

During a power outage, the grid tie inverter's built in AC transfer switch is activated which causes the inverter to disconnect from the grid as required by law for safety reasons and instead connnects the inverters output to an isolated subpanel that has been prewired to your home's emergency circuits. During daylight hours, during a power failure, energy from the solar panels is fed to the batteries through the charge controller and that energy is used to power the inverter which in turn powers the appliances that are connected to the isolated subpanel.

In the evening when the sun has gone down, the inverter produces power solely from the energy that has been stored in the batteries and the charging cycle is repeated the next day when the sun rises. As long as you don't discharge more energy from your batteries than is produced by your solar panels with a single day's worth of sunshine, then the cycle will continue indefinitely until the utility company's power has returned to normal operation.